One structure not mentioned yet in the connection is the Louvre Pyramid by I.M.Pei.
When considering which late 20th / early 21st century architects deserve the WH accolade, probably one criterium to consider would be whether that architect was influential in defining a new architectural style. (Many of the architects which have been awarded the Pritzker Prize seem still to be very much influenced by modernism.) Some of the styles that could be considered would be:
Brutalism: several British buildings would fit the bill as the representative icons of this movement, e.g. the Trellick Tower (
http://en.wikipedia.org/wiki/Trellick_Tower). My personal favourite, though, is the Bangladesh National Assembly building (
http://en.wikipedia.org/wiki/Jatiyo_Sangshad_Bhaban) by Louis Khan.
Metabolist movement: a Japanese architecture movement well represented by the Nakagin Capsule Tower (
http://en.wikipedia.org/wiki/Nakagin_Capsule_Tower) by Kurokawa.
High-Tech architecture: the Centre Pompidou in Paris by R Piano and R Rogers (
http://en.wikipedia.org/wiki/Centre_Georges_Pompidou), or the Lloyds building in London (
en.wikipedia.org/wiki/Lloyd's_Building) by R Rogers are good representatives of this style, where the "nuts and bolts" (and pipes, etc.) of a building are laid bare.
Postmodernism: the iconic builiding for this movement was the Portland Municipal Services Building, by M. Graves (
http://en.wikipedia.org/wiki/Portland_Building), built in 1982. However, the movement can be traced back to Robert Venturi - so a more relevant building may e.g. be the Vanna Venturi building. (
http://en.wikipedia.org/wiki/Vanna_Venturi_House)
Deconstructivism: two architects spring to mind here: Frank Gehry with in particular the Guggenheim Museum in Bilbao (
http://en.wikipedia.org/wiki/Guggenheim_Museum_Bilbao) - rarely has a single building completely redefined a whole city (Sydney being another example); and Zaha Hadid (
http://en.wikipedia.org/wiki/Zaha_Hadid), for which several buildings might classify, though it may still be too early to select one / some of her future creations might yet become the one defining Zaha Hadid building.
Other styles may be considered too.
An interesting site containing buildings from several contemporary architects is the
Vitra factory's area in Weil am Rhein, Germany - works of Pritzker Prize winners F Gehry, Z Hadid, Tadao Ando, Herzog & de Meuron, SANAA, Alvaro Siza are present there. In a sense, Weil am Rhein is a condensate of the architecture of the last two decades - and as such almost a cultural landscape of the 90s/2000s. See the following site for pictures of all the buildings of Weil am Rhein:
http://www.vitra.com/de-de/campus/architecture-tour/